Infrared Radiation in the Mesosphere and Lower Thermosphere: Energetic Effects and Remote Sensing

Abstract

This paper discusses the formation mechanisms of infrared radiation in the mesosphere and lower thermosphere (MLT), the energetic effects of the radiative absorption/emission processes, and the retrieval of atmospheric parameters from infrared radiation measurements. In the MLT and above, the vibrational levels of the molecules involved in radiative transitions are not in local thermodynamic equilibrium (LTE) with the surrounding medium, and this then requires specific theoretical treatment. The non-LTE models for CO2, O3, and H2O molecules are presented, and the radiative cooling/heating rates estimated for five typical atmospheric scenarios, from polar winter to polar summer, are shown. An optimization strategy for calculating the cooling/heating rates in general circulation models is proposed, and its accuracy is estimated for CO2. The sensitivity of the atmospheric quantities retrieved from infrared observations made from satellites to the non-LTE model parameters is shown.

Sharma R, Zygelman B, von Esse F, Dalgarno A (1994) On the relationship between the population of the fine structure levels of the ground electronic state of atomic oxygen and the translational temperature. Geophys Res Lett 21:1731–1734CrossRef